Yes, yes I am insane - M37

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Sep 17, 2006
Santa Rosa, CA
So, I know this is way outside the Toyota/Landcruiser theme of Mud, but I I think the peanut gallery will enjoy it.

I bought this thing in Grants Pass Oregon yesterday.






This was a fire engine in Yakima for a long time. They guy in Grants Pass had it for over 30 years. It's very, very original and in damn good shape - total of 40,000 miles - in theory. there's just one little spot of obvious rust.

My plan is to turn this into a fire truck for Rubicon Springs. That means it will go in with tank and pump in the back and probably never come out. Hopefully, there will never be needed for it's built purpose and instead it will be used to spray down kids on hot days or show off for Jamboree and Rubithon.

I see two options - well only one, really, but two just for fun. the idea is that this would super reliable and super durable and run down there for the next 30 years.

1. Leave it mostly stock. Clean out the fuel tank, probably replace the carb with a sniper, and call it good. The problems are
  • 24v - it could be converted to 12v
  • no power steering and it's not a light weight jeep
  • no power brakes
  • I have no idea how strong the axles or the transfer case are. It's a 3/4 ton truck - so they aren't huge.
  • We'd have to go new wheels and tires. similar size and style. It has the original military split rims.
If this set up breaks, the truck is down for a while and parts are hard to find and get

2. Modern drivetrain
  • Keep it leaf springs. It's fine.
  • Dana 60 front and rear with disc brakes and lockers, 5.83?
  • either
    • 5.7 with Sniper and 700R4 - this is the minimal technology, super reliable
    • 6.0 with Holley terminator and 4L80E - this is max power, max flexibility, and almost anyone can work on it.
    • Both of these are automatics as means anyone can drive it.
  • Altas 4
  • Radiator with fan
  • GM power steering system like an FJ40 retrofit. Keep the wheel (the cab is so cool!)
  • Power brakes (hydroboost?) - the pedal is
  • New wheels and tires. Find something that looks appropriate and try to go 40"
  • New drivelines
  • And blah blah blah etc., etc., etc.
I'm looking for help with this project. I don't want to take this on alone.
Nothing wrong here...

I vote for the more modern drivetrain. more universal and parts available. Why not look at Super Duty axles. A lot cheaper and through in a fuel injected engine and auto tranny. Should be a good project.
Late 90’s / early 2000’s 5.7 Vortec motors are still out there, make solid reliable power, and are cheap to put in anything with little fuss. Adding EFI like Sniper or such makes it super simple and has minimal sensors and electronics. I got my motor for $750, ran and drove until I tore it out. Bolts to almost any auto trans, add a really big cooler and go.

Also vote for modern axles for durability and parts availability. 14 bolt, sterling, something really beefy for the rear for that heavy water tank and plumbing
Very cool Peter :cool:
5.3/6.0LS and 4L80E pair out of a truck using the stock harness, case to match the axles you find, leaf springs for simplicity, less failure points, easier to trail fix should SHTF, cheaper.
Just a thought, but perhaps you can source one of the Japanese 70 series fire truck rear pump and tank equipment. The size is about the same. And it would be modern and likely in good repair--and not too expensive either.

And from this member of the gallery, I thank you for posting.

I think a lot about a Jeep station wagon from the 1950's I saw for sale somewhere in the Sierra Nevada mountains in the early 1970's, just when I was getting my drivers permit. I often think I should have tried to buy it. Of course the use was for high school commuting in LA so perhaps the 67 Bonneville convertible was a slightly more practical choice. But today I know which one I would rather have!
5.3/6.0LS and 4L80E pair out of a truck using the stock harness, case to match the axles you find, leaf springs for simplicity, less failure points, easier to trail fix should SHTF, cheaper.
No diesels as the springs. Simplifies what they have to bring in.

the stock engine is probably 50 hp and if anything breaks, it would be down for months.
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Love it!!! Now I’m not alone in my oddball M715 build!!
I've done a lot of work to one of those.

My impression is they were never intended to go over 35 MPH and they figured it would last about 4 minutes in battle so no need to put much thought into how it's put together.

I think for your purposes it would be best to gut the entire drivetrain. Everything under an M37 is a little terrible.

05+ Superduty axles would be my go to for a build like yours. Using all late Ford suspension, same as the axles, would be a straightforward solution and work fine with a heavy water tank.

An LS/4L80E would work well.

However, I would look real hard at a 5.7 Hemi. M37 is technically a Dodge and having done some projects with the late Hemi's I really like them. They all have their shortcomings, but the late Hemi is a very smart design. I'm not a Mopar fan at all, but I have had lots of LS's and Hemis apart and been involved with parts that go in both of them at the OEM level and the Hemi is not POS. It's a really good design and definitely prettier to look at than any LS.
I disagree that there was no thought put into them. They just lived in a world that didn't require going over 45. The primary reasons they are so scary is the steering setup, and they have the exact same steering as the Willys and the FJ40 had early on. It's a nightmare.

So, here's what I'm thinking right now. fire fighting skid is 800 lbs empty and 2500 full. Something like this.

So, current thinking is

Still thinking of staying leaf spring front and rear. Just not sure if the existing springs or mounting locations will work, or if the axles will force me to go outboard a little.
Dana 60 out of super duty front and rear - with air bags in the rear to help when the firefighting insert is in place. ARB lockers with onboard air to work the bags.

5.7 with sniper for absolute simplicity - probably a crate engine. Enough people are familiar with the sniper now that I think it's a better option that OEM ECM because you have some visibility and adjustability in the engine with the little 3.5" display. All new fuel system and sniper high pressure in tank pump.
Manual transmission (not sure which one yet). But, even a 4 speed would work.
Atlas 4 speed with 8:1 final ratio. that should be low enough to move around with full tank on the back.

And I'm leaning towards just going full hydro on the steering. It would need assist anyway, so, just go all the way.

All new brake setup to work the brakes on the Dana 60's. The brake pedal on the M37 goes down (it does not hang), so assuming it stays that way I'll need a frame mounted booster or a remote booster. I'm not real familiar with that world, so I'm learning. We could also convert to a hanging pedal assembly - it can't be that hard to shove something like a Jeep or FJ40 thing in - which might actually be easier in the end - for both brakes and clutch.

And, I REALLY want to keep the winch, so I have to figure out a way to run it - absent the PTO. But, the power steering pump just isn't big enough. Two power steering pumps? A separate large pump - can't be 12v.
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Consider Superduty leaf dana 60s have a poor turning radius. The coil axles can turn tighter and they are 35 spline+ better stub axle bearing+ better knuckles and balljoints+ stronger tie rods. The superduty leaf spacing could also appear funny under the narrow m37 frame. The coil axles have many advantages for roughly the same cost.

I liked the novelty of it, but after actually driving the through the floor pedals I did not like them. I put a lot of work into making those pedals work properly with newer clutch hydros and hydroboost master. If I did it again I would not even consider the floor pedals.
Not much help but it looks like it is going to be a cool project.

Id vote LS 4L80 and atlas for power train - potentially look at converting a 14 bolt for front and of course 14 bolt rear.
Okay, I'm getting closer to diving into this. Currently ... I haven't changed my mind a lot

6.2 LS3 with holley terminator - over 400 hp and 600 ft lb
There's a guy that EV converted an H1 Humvee with the electric motor out of an airplane tug, and that tempted me.
Manual transmission - not sure which one yet.
Atlas 2 speed or 4 speed.
Keep the leaf spring set up for simplicity. It seems like I won't have to move them, but I'm planning on putting new springs in.
I could link it. I'm still pondering the pros and cons. It's very much like 40 under there.
One of the great advantages of linking it is the height adjustability. for any given setup, you have a couple inches of adjustment. otherwise, you have to knwo your height from the beginning.
Dana 60 axles front and rear - 4.88? lockers.
I'm thinking 40's to match the scale of the beast.
All new cooling.
Electric brake booster
PSC PS pump
I'm not sure if I should do a 40 style PS conversion, or do it fj80 style.
The other option is just to jump to full hydro - still thinking
full hydro makes the 4 link conversion easier.
Keep the fuel tank where it is and rehab or replace - hopefully find a pump set up that will go in tank and will meet the 6.2's needs
Install bracket for drop down pedals (just figure out how to get a Jeep or FJ40 bracket to go in there), all new crap on the firewall for brakes and clutch.
All new harness - painless simple harness same as I've used the last few times.
Cage (although it ruins the look), sliders, skid plates

I really, really, really want to keep the winch operational - but PTO would be crazy - I think. So, I'm assuming that I can get a hydraulic pump to drive the winch. I'm assuming that I'd need an additional electric PS pump (to help out the PSC pump on the engine) to get enough flow. I'd use a pump similar to the on on my EV45.
I'm guessing I'd have to find someone to send the winch to for a rebuild, and I'd have to get clever about how to mount/mate/attach the hydraulic motor to the winch. But, I'm thinking it's doable. Just may not have a hell of a lot of pulling force. It's just not an M37 without that massive winch on the front.
Dana 60 rear will not last! I would at least do a 70, but an 80 or 14B would be the best. 14B are cheap!

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